1. Field of the Invention
This invention relates to a reproduction apparatus that can suitably be used for reproducing music from a music source that is obtained by recording in a concert hall or the like in a music listening room and also to a reproduction system configured by using a plurality of such reproduction apparatus.
2. Description of the Related Art
The acoustic characteristics of music listening rooms differ from room to room in terms of size, profile and internal decoration of the music listening room. Therefore, acoustic reproduction apparatus are marketed for the purpose of adjusting the acoustic characteristics of a music listening room to standardized ones or to those that match the taste of the listener.
For instance, such an acoustic reproduction apparatus is so designed as to irradiate a measuring signal for measuring the acoustic characteristics in the music listening room, collect responses (reflected sounds) and computationally determines the internal acoustic characteristics of the music listening room. Then, the apparatus computationally determines the correcting characteristics for correcting the acoustic characteristics in the music listening room and corrects the reproduced signals by means of the computationally determined correcting characteristics (Patent Document 1: Japanese Patent Application Laid-Open Publication No. 6-327089).
It is necessary to determine the transfer function from the position of the sound source to the listening position when measuring the internal acoustic characteristics of a music listening room. In the case of a music listening room, the position of the sound source is each of those of the speakers of the acoustic reproduction apparatus.
For example, the two speakers arranged at left and right front positions define respective sound source positions in an intensity stereo system. A 5.1 channel system comprises two speakers arranged respectively at left and right front positions, a speaker arranged at a central front position, two speakers arranged respectively at left and right rear positions and a woofer and these six speakers define respective sound source positions in the system. Thus, when speakers define respective sound source positions, the acoustic characteristics are measured for the speaker of each channel. Then, the transfer function of all the channels that are driven to operate is determined by computationally determining the sum of the transfer functions of all the channels.
The measuring microphone that is arranged at the listening position is either one that shows directional characteristics similar to those of the listener or a proximity 4 point microphone that can search for the positions of sound sources (Non-Patent Document 1: Yoshio Yamazaki, Tsuyoshi Ito, “Acoustic Measurement of a Concert Hall by a Proximity 4 Point Method”, JAS Journal, October, 1987).
Measuring microphones showing directional characteristics similar to those of the listener include dummy head microphones and simplified versions thereof include those buried in the surface of a spheroid prepared by simulating the human head at opposite lateral sides thereof
Methods of acquiring information on installation of audio systems and adjustment of acoustic characteristics of the audio system by way of a network and causing the audio system to automatically adjust the characteristics thereof have also been proposed.
With such a method, a center server is provided and a service system is built so as to comprise the center server and audio systems connected to the center server by way of a communication network. Then, the center server transmits data for adjusting audio equipment and data for installing audio equipment to each of the audio systems.
On the other hand, each of the audio systems is automatically adjusted for its characteristics by using the data for adjusting the audio equipment it has received. Additionally, the audio system displays the data for installing audio equipment it has received so that the user may install the audio equipment in a car by referring to the displayed method of installing the audio equipment (Patent Document 2: Japanese Patent Application Laid-Open Publication No. 2002-67815).
Non-Patent Document 2: Mikio Tohyama et al., “The Correlation Coefficient between the Two Ears in a Diffused and Reproduced Acoustic Space”, The Acoustic Society of Japan, Technical Committee of Psychological and Physiological Acoustics Group Data Book, H-84-28, 1984 is known.